Error type: "Forbidden". Error message: "The request cannot be completed because you have exceeded your quota." Domain: "youtube.quota". Reason: "quotaExceeded".

Did you added your own Google API key? Look at the help.

Check in YouTube if the id PLScC8g4bqD47c-qHlsfhGH3j6Bg7jzFy- belongs to a playlist. Check the FAQ of the plugin or send error messages to support.